Ceiling fans have become increasingly popular in homes and businesses. With the increasing popularity of ceiling fans came the concern that the dynamic loads of an unbalanced ceiling fan could cause the mounting flanges of the ceiling boxes to flex and eventually break off. This concern lead to code provisions that required ceiling boxes intended to be used as the sole support of ceiling fans to be tested and listed for that use.
As a result, electrical boxes were developed that more securely support ceiling fans and that satisfy the pertinent code provisions and the relevant tests of Underwriter's Laboratories. However, the advancement in this area does not satisfy every need of consumers who desire ceiling fans. Specifically, there remains the problem of electrical boxes that were made and installed prior to the new code provisions, and were not specifically designed to support ceiling fans. These prior electrical boxes are not capable of using the prior electrical box to securely support a ceiling fan. Thus, such prior electrical boxes must be replaced, causing added expense and inconvenience. Additionally, it is expensive for manufacturers of prior electrical boxes to redesign and produce a new product.
Many of prior electrical boxes designed only for lighting fixtures are designed to be mounted to a support member, such as a joist or a truss. With these particular electrical boxes, the problem is three-fold. First, the tabs of the electrical box are not strong enough to support the dynamic loading of the ceiling fan. Second, the box mounting brackets are typically projection welded to the box and cannot stand up to the dynamic loads of ceiling fans. (This is especially true with an out of balance ceiling fan.) Third, the connection between the electrical box bracket and the joist or truss is also deficient. This connection is usually made with nails or staples into the joist or truss.
Examples of some prior electrical boxes are disclosed in U.S. Pat. No. 1,748,693 to Adell; U.S. Pat. No. 1,800,484 to Thomas, Jr.; U.S. Pat. No. 1,966,451 to Manquais; U.S. Pat. No. 3,474,994 to Swanquist; U.S. Pat. No. 3,724,795 to Callanan; U.S. Pat. No. 4,880,128 to Jorgensen; U.S. Pat. No. 4,892,211 to Jorgensen; U.S. Pat. No. 4,988,067 to Propp et al.; Re. 34,603 to Caison et al.; and U.S. Pat. No. 5,407,088 to Jorgensen et al.
Thus, there is a continuing need to provide improved electrical boxes, especially those that can be attached to support members such as a joist or a truss. Additionally, there is a continuing need to provide a method of modifying existing electrical boxes that are intended to be coupled to a support member such as a joist or truss so that they may securely support ceiling fans. This invention addresses these needs in the art as well as other needs which will become apparent to those skilled in the art once given this disclosure.